It happened as police were monitoring Summerfest traffic after Summerfest Opening Day Wednesday.

According to officials, police stopped the vehicle for speeding prior to the delivery. Officials say the couple was en route to the hospital -- after mom went into labor while watching the Summerfest fireworks!

Officer Xavier Benitez and Adam Bradley thought they had a drunk on their hands as they gave chase to a speeding car.

"We saw a red car just blowing through the red lights, blaring its horn," Benitez said.

"It took us like, 50 miles-an-hour to catch him in a two-block radius," Bradley said.

At first, what police saw and heard caused a bit of confusion.

"We heard a female moaning in pain," Bradley said.

That's when police jumped into action -- delivering a baby near St. Paul and Water Street.

"As I approached, I saw she was actually giving birth. The head was fully crowned and everything. At that point I yelled across to my partner, 'we're having a baby!'" Benitez said.

North Avenue was blocked for Summerfest's fireworks, and the area was congested due to Summerfest traffic. Officers knew there wasn't enough time to get to the hospital.

Two minutes later, a baby girl was born.

"I was basically playing the catcher and Isabella came out. I immediately tried to clear the airways and remove the umbilical cord. My partner's assisting, flicking on the feet to get a response," Benitez said.

Paramedics and other squads showed up, put the baby in a blanket and whisked the mom and baby to Columbia St. Mary's Hospital.

"We were kind of both in awe. I recently am a father, so I kind of know what was happening," Benitez said.

The officers took the baby's dad, and five-year-old sibling, who was also in the car, to the hospital to join mom and baby.

"I was gleaming ear to ear," Benitez said.

"I've been at plenty of shooting scenes. We've taken plenty of people into custody, but to be able to bring a life into the world, it's just amazing," Bradley said.

The officers who helped out Wednesday night were able to visit with Isabella and her family, and say all are doing great.